I recently re-read and re-watched the 2009 Gathering of the Gargoyles Radio Play: "Religious Studies 101: A Handful of Thorns." It is a non-canonical crossover between "Gargoyles" and "The Spectacular Spider-Man" written by Greg Weisman and performed by several of the original voice actors and some fans.
In the play, Demona obtains the Spear of Destiny. A little tidbit just leaped out at me. A line of Demona's from the script:
"A simple wooden shaft. The prize of Adolph Hitler's personal collection. After his... demise, his remaining followers smuggled it to Brazil. I paid handsomely to have it smuggled to me."
Which leads me to wonder. Did Demona have a connection with Hitler? Now, I know the Radio Play is non-canonical, but Greg did keep everyone in character and said elements of the Play might end up in future canon stories.
The way she mentions his demise in the script, and the way Marina delivered the line, it is quite... suspicious.
We know that Demona is perfectly willing to ally herself with humans when it suits her purposes. She allied herself with Hakon and the Captain. She allied herself with Canmore (and, I tend to think that as far as Demona is concerned, the scars of the Hunter are a far more evil symbol than the swastika). She allied herself with Xanatos.
Hitler had a personal obsession with the occult, that is a widely known fact, and he never kept it a secret, even then. Demona could have easily found out about that, and worked with him to achieve her own ends.
Greg Weisman also has spent the last thirteen years refusing to tell us what Demona did during World War II. He did tell us that Macbeth fought for the Allies though. And we know she most likely didn't encounter any Hunters since the last documented encounter before Charles Canmore in 1980 was Fiona Canmore in 1920.
Although, there was this question and answer about Demona and the War:
5) What did Demona think of stuff like the Holocaust or slavery? I know it probably confirmed her beliefs on the evil of humanity, but did she feel sorry for the victims involved?
5. Generally, I think your first statement is correct. Whether or not she felt individual pity has a lot to do with how close she got to the action, which I'm not commenting on at this time.
With that last sentence, I am reasonably sure that he has something in mind.
Yes, Demona never hesitates to point of humanity's evils, but she is also enough of a hypocrite to participate and cooperate with the worst of humanity when it suits her needs.
I'll leave you all with this documentary on Hitler and the occult.